A few years ago I discovered a website showing the photographs of a certain Russian photographer, Prokudin-Gorskii, that were all developed in colour! It was the most amazing thing ever, to see authentic scenes from over 100 years ago in full colour. Apparently he had developed a special process for developing in colour, but the photos were subsequently lost during the Russian Revolution and only resurfaced later. I often use theses images for reference because they are so vivid.
There is also a very interesting section on the website about re-creating his colour process but using digital methods.
We tend to think of the past in black and white or in sepia tones, so to see it in colour reminds us that those people in the photos really did exist. Here is a selection of my favourites: